Help: unfamiliar_opponents

UNFAMILIAR OPPONENTS
ZombieMUD features a system which gives you a bonus of EXP for slaying NPCs
you have not killed in the very recent past. This is because you learn more
fighting an opponent whose method of combat you are less than familiar with.
This bonus resets at reboot and will return on its own, if you refrain from
killing the same type of monster of a long period of time. You get this bonus
both while partying and when you play alone, and when you gain it, you will
get a message about it when your opponent dies. The size of the bonus gained
depends on how long it has been since you last killed the same enemy, and
the size of your party. The bigger the party, the bigger the bonus gets.
Because this bonus is personal and applies only to you, it does not show in
party kills. You can see it by watching your exp amount, or in your summary.